Effects of computer keyboarding on ultrasonographic measures of the median nerve

Convolutional Neural Network Approaches in Median Nerve Morphological Assessment from Ultrasound Images

Ultrasound imaging has been used to investigate compression of the median nerve in carpal tunnel syndrome patients. Ultrasound imaging and the extraction of median nerve parameters from ultrasound images are crucial and are usually performed manually by experts. The manual annotation of ultrasound images relies on experience, and intra- and interrater reliability may vary among studies. In this study, two types of convolutional neural networks (CNNs), U-Net and SegNet, were used to extract the median nerve morphology. To the best of our knowledge, the application of these methods to ultrasound imaging of the median nerve has not yet been investigated. Spearman's correlation and Bland-Altman analyses were performed to investigate the correlation and agreement between manual annotation and CNN estimation, namely, the cross-sectional area, circumference, and diameter of the median nerve. The results showed that the intersection over union (IoU) of U-Net (0.717) was greater than that of SegNet (0.625). A few images in SegNet had an IoU below 0.6, decreasing the average IoU. In both models, the IoU decreased when the median nerve was elongated longitudinally with a blurred outline. The Bland-Altman analysis revealed that, in general, both the U-Net- and SegNet-estimated measurements showed 95% limits of agreement with manual annotation. These results show that these CNN models are promising tools for median nerve ultrasound imaging analysis.

Effects of 1-hour computer use on ulnar and median nerve conduction velocity and muscle activity in office workers

OBJECTIVES

To compare the effects of 1-hour computer use on ulnar and median nerve conduction velocity and muscle activity in office workers with symptomatic neck pain and asymptomatic office workers.

METHODS

A total of 40 participants, both male and female office workers, with symptomatic neck pain (n = 20) and asymptomatic (n = 20), were recruited. Pain intensity, ulnar nerve conduction velocity, median nerve conduction velocity, and muscle activity were determined before and after 1 hour of computer use.

RESULTS

There was a significant increase in pain intensity in the neck area in both groups (P < .001). The symptomatic neck pain group revealed a significant decrease in the sensory nerve conduction velocity of the ulnar nerve (P = .008), whereas there was no difference in the median nerve conduction velocity (P > .05). Comparing before and after computer use, the symptomatic neck pain group had less activity of the semispinalis muscles and higher activity of the anterior scalene muscle than the asymptomatic group (P < .05). The trapezius and wrist extensor muscles showed no significant differences in either group (P > .05).

CONCLUSIONS

This study found signs of neuromuscular deficit of the ulnar nerve, semispinalis muscle, and anterior scalene muscle after 1 hour of computer use among office workers with symptomatic neck pain, which may indicate the risk of neuromuscular impairment of the upper extremities. The recommendation of resting, and encouraging function and flexibility of the neuromuscular system after 1 hour of computer use should be considered.

Occupational and non-occupational risk factors correlating with the severity of clinical manifestations of carpal tunnel syndrome and related work disability among workers who work with a computer

The contribution of certain occupational and personal factors to the development of carpal tunnel syndrome (CTS) is still uncertain. We investigated which specific occupational and non-occupational factors correlate with the level of clinical manifestations and work disability related to CTS. The study included 190 workers who work with a computer and have diagnosed CTS (100 men, 90 women, aged 20-65 years). Subjective experience of CTS-related impairments was assessed with the Symptom Severity Scale (SSS) and the Functional Status Scale (FSS) of the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ). The objective, neural impairments were tested with electrodiagnostics (EDX), whereas CTS-related work disability data were collected from medical records. We found a high inter-correlation between BCTQ, EDX, and work disability data. These also showed high correlations with certain occupational factors (duration of computer-working in months and hours spent daily in computer-working, certain ergonomic, microclimatic, and other occupational conditions) and non-occupational factors (demographic and lifestyle factors: nutritional status, diet, smoking, alcohol consumption, and physical activity). Despite its limitations, our study has identified occupational and non-occupational risk factors that can aggravate CTS and work disability, but which can also be improved with workplace and lifestyle preventive and corrective measures. More research is needed, though, to establish the possible causal relationships and the independent influence of each of those risk factors.

The effect of anthropometric characteristics and electronic device use on median nerve cross-sectional area: A cross-sectional study

INTRODUCTION

This study aimed to identify the relationship between age, body mass index (BMI), weight, height, and wrist circumference and median nerve cross-sectional area (CSA). The study also aimed to examine the difference between CSA in individuals reporting a high amount (>4 hours per day) of electronic device use compared to those reporting a low amount (≤4 hours per day).

MATERIALS/METHODS

One hundred twelve healthy individuals volunteered to participate in the study. Anthropometric, demographic, and self-reported electronic device usage data were collected. A transverse image of the median nerve was captured using ultrasonography from the dominant wrist at the carpal tunnel inlet . A Spearman's rho correlation coefficient was used to examine correlations between participant characteristics (age, BMI, weight, height, and wrist circumference) and CSA. Separate Mann-Whitney U tests were used to examine differences in CSA in those younger and older than age 40, in those with BMI <25 kg/m2 and BMI ≥25 kg/m2, and in high and low-frequency device users.

RESULTS

BMI, weight, and wrist circumference showed fair correlations with CSA. There were significant differences in CSA between individuals younger than 40 and those older than 40 and between individuals with BMI <25kg/m2 and those with BMI ≥25kg/m2. There were no statistically significant differences in CSA in the low- and high-use electronic device groups.

DISCUSSION

Anthropometric and demographic characteristics including age and BMI or weight should be considered when examining the CSA of the median nerve, especially when determining cut-off points for establishing a diagnosis of carpal tunnel syndrome.

Sonographic reference values for median nerve cross-sectional area: A meta-analysis of data from healthy individuals

Objective

Establish median nerve CSA reference values and identify patient-level factors impacting diagnostic thresholds.

Methods

Studies were identified through a robust search of multiple databases, and quality assessment was conducted using a modified version of the National Institute of Health Study Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. A meta-analysis was performed to identify normative values stratified by anatomic location. A meta-regression was conducted to examine heterogeneity effects of age, sex, and laterality.

Results

The meta-analysis included 73 studies; 41 (56.2%) were high quality. The median nerve CSA [95% CI] was 6.46mm2 [6.09-6.84], 8.68mm2 [8.22-9.13], and 8.60mm2 [8.23-8.97] at the proximal forearm, the carpal tunnel inlet, and the proximal carpal tunnel, respectively. Age was positively associated with CSA at the level of proximal carpal tunnel (β=0.03mm2, p=0.047). Men (9.42mm2, [8.06-10.78]) had statistically larger proximal tunnel CSA (p = 0.03) as compared to women (7.71mm2, [7.01-8.42]). No difference was noted in laterality.

Conclusion

A reference value for median nerve CSA in the carpal tunnel is 8.60mm2. Adjustments may be required in pediatrics or older adults. The diagnostic threshold of 10.0mm2 for male patients should be cautiously applied as the upper limit of normative averages surpasses this threshold.

A systematic review of the methodology of sonographic assessment of upper limb activities-associated carpal tunnel syndrome

BACKGROUND

Various upper limb activities were speculated to be associated with the development of carpal tunnel syndrome (CTS). Nonetheless, there are currently no standardization on the uses of parameters in CTS assessments, nor are there any conclusive findings regarding the usefulness of various sonographic measurements in studies of different upper limb activities. In this review, we intend to evaluate the methodology of assessing CTS induced by upper limb activities with ultrasonographic technique and provide corresponding suggestions.

METHODS

Clinical studies on the association between upper limb activities and prevalence of CTS using ultrasonography were recruited in a database research on the basis of a procedural selection criteria and reviewed. The following qualitative items were extracted: characteristics of studies, scanning methods, selection of sonographic parameters, and related article findings.

RESULTS

Eleven studies were qualified for this review. Three studies were computer keyboard typing related, five studies were electronic device related, and three studies were wheelchair-related. All sampled articles included cross-sectional area (CSA) at the pisiform level. The swelling ratio (SR) and flattening ratio (FR) at the hamate level are also used in most studies in addition to the CSA at the pisiform level. The effectiveness of such parameters is subjected to various confounding factors such as age, weight, body mass index, and wrist anthropometrics, suggesting CSA and SR with sufficient levels had significant values as sonographic parameters. Values of parameters were found affecting symptomatic signs and hand dominance.

CONCLUSION

Ultrasound scan is a suitable tool to assess the relationship between upper limb activity and CTS. CSA at the pisiform level and SR and the FR at the hamate levels are generally suitable in upper limb-associated CTS investigations. Specific study designs are required to eliminate different confounding factors accordingly.

Comparing Shape Categorization to Circularity Measurement in the Evaluation of Median Nerve Compression Using Sonography

Purpose

This study aimed to develop a subjective categorization of nerve shape and to examine the relationship of shape categorizations to measurement of nerve circularity.

Methods

Wrists were evaluated with sonography in healthy participants. Images of the median nerve were obtained in the transverse plane at the level of pisiform with the fingers resting, gripping, and pinching. Nerves were categorized as ovoid, angular, or irregular, and the cross-sectional area and perimeter were measured to calculate nerve circularity.

Results

Across 167 participants, the median nerve shifted from being primarily ovoid at rest to angular shaped when the fingers were in a full fist or pinching. Approximately three-quarters of subjects exhibited a shape change during dynamic movement. Irregular nerves had the lowest circularity values; however, the majority of nerves had similar circularity measures despite having different shapes.

Conclusions

Subjective categorization of shape has the potential to be a valid technique for evaluation of the median nerve using sonography, and this evaluation may provide additional information regarding nerve compression that is not fully captured by a circularity measure. Further investigation is needed to determine how these two techniques may be best used individually or together to advance clinical diagnosis, prevention, and rehabilitative interventions.

Morphological Changes of the Median Nerve Within the Carpal Tunnel During Various Finger and Wrist Positions: An Analysis of Intensive and Nonintensive Electronic Device Users

PURPOSE

To investigate the effects of static hand postures during various finger and wrist positions on morphological changes of the median nerve within the carpal tunnel in intensive and nonintensive electronic device users.

METHODS

Forty-eight university students, equally divided into intensive and nonintensive users (≥5 h/d and <5 h/d of electronic device usage, respectively), were randomly selected after questionnaire responses and evaluated clinically and by ultrasonography.

RESULTS

Intensive users reported more wrist/hand pain with a high severity score than nonintensive users. They also had larger median nerve cross-sectional areas, flattening ratios, and perimeters than nonintensive users, and showed less median nerve deformation under various finger and wrist positions. Compared with the neutral wrist position with all fingers extended for both intensive and nonintensive users, the cross-sectional areas decreased under finger flexion and grip, as well as wrist extension-flexion and radial-ulnar deviation. Overall, the average median nerve size of the dominant hand was much larger than that of the nondominant hand, especially for intensive users.

CONCLUSIONS

Wrist deviation from neutral can lead to more pronounced deformation of the median nerve than finger flexion for both intensive and nonintensive users. To minimize compression on the median nerve, it is important to keep the wrist as near to the neutral position as possible during computer-related work and avoid keeping the thumb and fingers in a static flexed position when using mobile devices, especially for single-hand use.

CLINICAL RELEVANCE

On the basis of this observational study, intensive users had enlarged and flattened median nerves as well as decreased nerve deformation during hand motions compared with nonintensive users. As overuse of electronic devices may adversely affect the median nerve, caution may be warranted.

Keyboards types of selected electronic devices and the occurrence of pain in the shoulder girdle and upper limb - a review of literature

Introduction: Nowadays, computers, personal telephones (smartphones) and other electronic devices are widely used in many areas of everyday life, making them indispensable tools in the workplace, as well as other environments, e.g. at home. Studies from recent years have shown that the mere use of a computer keyboard for many hours carries the risk of pain in the hand, forearm, arm, shoulder girdle, neck and other parts of the motor organs. Aim: The aim of the literature review carried out in this work was to determine what potential threats are posed by standard keyboards and smartphone touch keypads, as well as the comparison of standard and ergonomic keyboards. Material and methods: The following databases were searched: PubMed, ResearchGate and Cochrane Library, in which 13 articles meeting the inclusion and exclusion criteria were found (6 regarding standard keyboards, 3 concerning ergonomic keyboards and 4 related to smartphone keypads). Results: The results of these studies indicate exposure to dysfunctions of the musculoskeletal system associated with typing on keyboards, especially when writing fast, with high pressure, in unnatural positions of the wrists and forearms and during long-term writing. Ergonomic keyboards can be a good alternative to standard keyboards, especially for those who use one for more than four hours a day. This literature review indicates the need for more research, especially randomized clinical trials among a large population. Conclusions: 1. The use of keyboards of selected electronic devices with different ergonomic characteristics has an adverse effect on the functionality of the shoulder girdle and upper limb, mainly generating painful symptoms with different clinical characteristics. 2. The most important influence on the occurrence of functional disorders and pain complaints concerning the shoulder girdle and upper limb when using a keyboard with different ergonomic characteristics regards the strength of pressure on the keys, speed of typing as well as long-lasting and forced positioning of the wrists and forearms. Keyboards, ergonomics, pain

Impact of keyboard typing on the morphological changes of the median nerve

Objectives:

The primary objective was to investigate the effects of continuous typing on median nerve changes at the carpal tunnel region at two different keyboard slopes (0° and 20°). The secondary objective was to investigate the differences in wrist kinematics and the changes in wrist anthropometric measurements when typing at the two different keyboard slopes.

Methods:

Fifteen healthy right-handed young men were recruited. A randomized sequence of the conditions (control, typing I, and typing II) was assigned to each participant. Wrist anthropometric measurements, wrist kinematics data collection and ultrasound examination to the median nerve was performed at designated time block.

Results:

Typing activity and time block do not cause significant changes to the wrist anthropometric measurements. The wrist measurements remained similar across all the time blocks in the three conditions. Subsequently, the wrist extensions and ulnar deviations were significantly higher in both the typing I and typing II conditions than in the control condition for both wrists (p<0.05). Additionally, the median nerve cross-sectional area (MNCSA) significantly increased in both the typing I and typing II conditions after the typing task than before the typing task. The MNCSA significantly decreased in the recovery phase after the typing task.

Conclusions:

This study demonstrated the immediate changes in the median nerve after continuous keyboard typing. Changes in the median nerve were greater during typing using a keyboard tilted at 20° than during typing using a keyboard tilted at 0°. The main findings suggest wrist posture near to neutral position caused lower changes of the median nerve.

Effects of electronic device overuse by university students in relation to clinical status and anatomical variations of the median nerve and transverse carpal ligament

INTRODUCTION

This study investigates the results of a questionnaire, provocative tests, and ultrasonographic measurements of carpal tunnel morphological parameters in intensive and nonintensive electronic device users.

METHODS

Forty-eight university students (equal numbers of intensive and nonintensive users, ≥5 h/day and <5 h/day of electronic device usage, respectively) were randomly selected after questionnaire responses were received and evaluated clinically and by ultrasonography. All participants were right-handed.

RESULTS

Intensive users had significantly more positive results in Phalen's and Durkan's tests and reported more wrist/hand pain compared with nonintensive users (P < 0.05). Intensive users also had significantly larger median nerve cross-sectional areas, flattening ratios, and perimeters as well as greater bowing of the transverse carpal ligament compared with nonintensive users (P < 0.05).

DISCUSSION

Overuse of electronic devices may adversely affect the median nerve within the carpal tunnel and the transverse carpal ligament, resulting in numbness, tingling, and pain in the hand. Caution may be warranted when using handheld electronic devices. Muscle Nerve 56: 873-880, 2017.

Effect of the release exercise and exercise position in a patient with carpal tunnel syndrome

[Purpose] This study examined the effect of the release exercise and exercise position in carpal tunnel syndrome (CTS). [Subject] A 40-year-old, right-hand-dominant man presented with CTS, with pain and progressive tingling and numbness in the right hand. [Methods] The subject performed three exercises: (1) release, (2) wrist flexor stretching, and (3) wrist extensor stretching. In session 1, the subject performed exercises 2 and 3 in the standing position for 2 weeks. In session 2, the subject performed all three exercises in the supine position for 2 weeks. [Results] The pressure pain threshold decreased after session 1 and decreased further after session 2, and the Phalen’s test and Tinel sign became progressively less positive. [Conclusion] Exercises in the supine position, including release exercises, are recommended for CTS.

Occupational mononeuropathies in industry

Peripheral nerve injuries have the potential to cause significant disability and can be commonly associated with recreational and occupational activities. Acute nerve injuries are mainly related to violent trauma, while repeated mechanical trauma due to external forces or repetitive motions can produce chronic nerve compression injury. This chapter will present a narrative review of the existing evidence of the association between peripheral compressive nerve disorders and work-related risk factors. Carpal tunnel syndrome (CTS) is the most common peripheral neuropathy in the general population and in working populations employed in manual repetitive and forceful activities. The work-relatedness of CTS is essentially based on epidemiologic evidence and the results of experimental studies showing the capability of repetitive wrist extreme postures, associated with hand-wrist forceful exertions, to increase the pressure inside the carpal tunnel and to compress the median nerve. Assembly industry, food processing and packaging, hand-arm vibrating tools, and jobs involving high-repetition, high-force tasks put workers at risk for CTS. Less strong evidence exists of the association between ulnar elbow neuropathy and manual tasks or repetitive stretch on squatting and peroneal nerve neuropathy at the fibular head. Very few reports are available about the association between occupation and other compressive peripheral nerve injuries.

Computer keyboarding biomechanics and acute changes in median nerve indicative of carpal tunnel syndrome

BACKGROUND

Carpal tunnel syndrome is a common and costly peripheral neuropathy. Occupations requiring repetitive, forceful motions of the hand and wrist may play a role in the development of carpal tunnel syndrome. Computer keyboarding is one such task, and has been associated with upper-extremity musculoskeletal disorder development. The purpose of this study was to determine whether continuous keyboarding can cause acute changes in the median nerve and whether these changes correlate with wrist biomechanics during keyboarding.

METHODS

A convenience sample of 37 healthy individuals performed a 60-minute typing task. Ultrasound images were collected at baseline, after 30 and 60 min of typing, then after 30 min of rest. Kinematic data were collected during the typing task. Variables of interest were median nerve cross-sectional area, flattening ratio, and swelling ratio at the pisiform; subject characteristics (age, gender, BMI, wrist circumference, typing speed) and wrist joint angles.

FINDINGS

Cross-sectional area and swelling ratio increased after 30 and 60 min of typing, and then decreased to baseline after 30 min of rest. Peak ulnar deviation contributed to changes in cross-sectional area after 30 min of typing.

INTERPRETATION

Results from this study confirmed a typing task causes changes in the median nerve, and changes are influenced by level of ulnar deviation. Furthermore, changes in the median nerve are present until cessation of the activity. While it is unclear if these changes lead to long-term symptoms or nerve injury, their existence adds to the evidence of a possible link between carpal tunnel syndrome and keyboarding.

Effect of wrist angle on median nerve appearance at the proximal carpal tunnel

This study investigated the effects of wrist angle, sex, and handedness on the changes in the median nerve cross-sectional area (MNCSA) and median nerve diameters, namely longitudinal diameter (D1) and vertical diameter (D2). Ultrasound examination was conducted to examine the median nerve at the proximal carpal tunnel in both dominant and nondominant hands of men (n = 27) and women (n = 26). A total of seven wrist angles were examined: neutral; 15°, 30°, and 45° extension; and 15°, 30°, and 45° flexion. Our results indicated sexual dimorphism and bilateral asymmetry of MNCSA, D1 and D2 measurements. MNCSA was significantly reduced when the wrist angle changed from neutral to flexion or extension positions. At flexion positions, D1 was significantly smaller than that at neutral. In contrast, at extension positions, D2 was significantly smaller than that at neutral. In conclusion, this study showed that MNCSA decreased as the wrist angle changed from neutral to flexion or extension positions in both dominant and nondominant hands of both sexes, whereas deformation of the median nerve differed between wrist flexion and extension.

Computer use and carpal tunnel syndrome: A meta-analysis

BACKGROUND

Studies have reported contradictory results on the role of keyboard or mouse use in carpal tunnel syndrome (CTS). This meta-analysis aimed to assess whether computer use causes CTS.

METHODS

Literature searches were conducted in several databases until May 2014. Twelve studies qualified for a random-effects meta-analysis. Heterogeneity and publication bias were assessed.

RESULTS

In a meta-analysis of six studies (N=4964) that compared computer workers with the general population or other occupational populations, computer/typewriter use (pooled odds ratio (OR)=0.72, 95% confidence interval (CI) 0.58-0.90), computer/typewriter use ≥1 vs. <1h/day (OR=0.63, 95% CI 0.38-1.04) and computer/typewriter use ≥4 vs. <4h/day (OR=0.68, 95% CI 0.54-0.87) were inversely associated with CTS. Conversely, in a meta-analysis of six studies (N=5202) conducted among office workers, CTS was positively associated with computer/typewriter use (pooled OR=1.34, 95% CI 1.08-1.65), mouse use (OR=1.93, 95% CI 1.43-2.61), frequent computer use (OR=1.89, 95% CI 1.15-3.09), frequent mouse use (OR=1.84, 95% CI 1.18-2.87) and with years of computer work (OR=1.92, 95% CI 1.17-3.17 for long vs. short). There was no evidence of publication bias for both types of studies.

CONCLUSIONS

Studies that compared computer workers with the general population or several occupational groups did not control their estimates for occupational risk factors. Thus, office workers with no or little computer use are a more appropriate comparison group than the general population or several occupational groups. This meta-analysis suggests that excessive computer use, particularly mouse usage might be a minor occupational risk factor for CTS. Further prospective studies among office workers with objectively assessed keyboard and mouse use, and CTS symptoms or signs confirmed by a nerve conduction study are needed.

The deformation and longitudinal excursion of median nerve during digits movement and wrist extension

The use of electronic devices, such as mobile phones and computers, has increased drastically among the young generation, but the potential health effects of carpal tunnel syndrome (CTS) on university students has not been comprehensively examined. Thirty-one university students aged 18 to 25 y with no symptoms of CTS were successfully recruited in this study. By using noninvasive ultrasonography, the morphological characteristics of the median nerve of each volunteer, and the extent of its longitudinal excursion movement under experimental conditions, in which a real operating environment of electronic devices was simulated, were quantified. The results demonstrated that the median nerve at the carpal tunnel inlet was flattened during wrist extension: the flattening ratio increased from 3.40 ± 0.91 at the neutral position to 4.10 ± 1.11 at the angle of 30° and 4.09 ± 1.11 at the angle of 45°. In addition, the median nerve became swollen after the students performed rapid mobile-phone keying for 5 min, indicated by a significant increase in the cross-sectional area from 6.05 ± 0.97 mm(2) to 7.56 ± 1.39 mm(2). Passive longitudinal excursion was observed at the median nerve when the students performed mouse-clicking (2.4 ± 1.0 mm) and mobile-phone keying tasks (1.7 ± 0.6 mm), with the mouse-clicking task generating a greater extent of longitudinal excursion than the mobile-phone keying task did. In conclusion, the findings of the present study verify the potential harm caused by using electronic devices while maintaining an inappropriate wrist posture for a substantial period.

Repetitive differential finger motion increases shear strain between the flexor tendon and subsynovial connective tissue

Non-inflammatory fibrosis and thickening of the subsynovial connective tissue (SSCT) are characteristic in carpal tunnel syndrome (CTS) patients. These pathological changes have been linked to repetitive hand tasks that create shear forces between the flexor tendons and SSCT. We measured the relative motion of the flexor digitorum superficialis tendon and SSCT during two repetitive finger tasks using color Doppler ultrasound. Twelve participants performed flexion-extension cycles for 30 min with the long finger alone (differential movement) and with all four fingers together (concurrent movement). Shear strain index (SSI, a relative measure of excursion in flexion and extension) and maximum velocity ratio (MVR, the ratio of SSCT versus tendon during flexion and extension) were used to represent shear. A linear effect of exertion time was significant and corresponded with larger tendon shear in differential motion. The flexion SSI increased 20.4% from the first to the 30th minute, while MVR decreased 8.9% in flexion and 8.7% in extension. No significant changes were found during concurrent motion. These results suggest that exposure to repetitive differential finger tasks may increase the risk of shear injury in the carpal tunnel.